Actually plain soap doesn't do shit. It's an emulsifier, not a panacea. Plain soap simply binds oils and water, the theory being that if you take the oil off your skin you're magically "clean". It does not "kill" "germs" (the non-scientific catchall term which includes viruses which aren't even alive in the first place according to the classical definition of life) any more than other emulsifiers like lecithin or egg yolks do.
Soap is a detergent which is a class of surfactant which is a class of emulsifier. You're being a little too general in classing egg yolks with soap.
Soap helps you remove bacteria embedded in the grease on your skin. Washing with soap and water removes most of the harmful bacteria that might cause nasty stomach issues or serious infections while leaving behind the generally "beneficial" bacteria.
This place just isn't big enough for all of us. We've got to find a way off this planet.